The present invention relates to the field of emergency radio transmitters and more particularly to emergency transmitters that are automatically activated in case of an accident.
Air and ground transport vehicles frequently have accidents in remote areas. Often the occurrence of the accident is not known and the location may be hidden from view. When such incidents happen, and the proper agencies notified, search and rescue teams may be mobilized. Often the teams must first search over wide areas in order to locate the damaged vehicle and its occupants. This search and rescue process takes considerable time and as a result the chances of saving lives are greatly reduced.
Of course two way microwave radios or cellular phones may fulfill the function of accident notification but only if the persons involved in the accident possess such devices and are sufficiently alert and knowledgeable to provide required location information, and the vehicle is not in a location that precludes line-of-sight communication. This presupposes the ability for signals from the devices reaching a suitable receiver or repeater station in order to alert a known rescue function, which must then have sufficient information to search in close proximity to the accident location. While they may or may not be suitable, two way radios and cell phones, and cell phone systems such as GM's "On-Star" or Ford's "Rescu", are expensive and inefficient ways of accomplishing the goal of remote accident notification. For example the Mayday Operational Test Report.sup.1 supported by Federal Highway Funding shows only 80% data connection rate using cell phones.
 FNT .sup.1 Castle Rock Consultants, October 1997, p. 30, Table 51
What is needed to help save lives, is an emergency locating transmitter that is automatically activated in case of an accident and that generates a rescue signal that is broadcast to multiple rescue resources with an infallible assurance of a rescue result. Development of a system which can broadcast such a locating signal in case of an accident even without the need of a live voice to send a message relative to the identification and location of the vehicle represents a great improvement in the field of transportation safety communication and satisfies a long felt need of security agencies and the traveling public.